Unable to login to Symantec Endpoint Protection Manager

Hello,

I have upgraded Symantec Endpoint Protection Manager from 11.0 to 12.1 in our VM machine, howevr someone mistakenly revert the snapshot of the VM to the previous date and after that whenever I am trying to login to the console using credentail admin, it gives me the below error

"Failed to connect to the server.

Make sure that the server is running and your session has not timed out. If you can reach the server but cannot logon, make sure that you provided the correct parameters.if you are experiencing network issues, contact your system administrator"

Please help for resolving the issue.

I have tried the steps as mentioned in below URL, but of no help

http://www.symantec.com/business/support/index?page=content&id=TECH104931&profileURL=https%3A%2F%2Fsymaccount-profile.symantec.com%2FSSO%2Findex.jsp%3FssoID%3D1369630251637LQq92944100l8787gqb7RNKu1Q022KwA824zy